This invention relates to improvements in scroll compressor housings.
Scroll compressors are being utilized in many refrigerant compression operations, since they have many functional benefits when compared to other types of compressors. Thus, scroll compressors are becoming adopted by the compression industry for many applications. There are challenges, however, with scroll compressors.
Typically, a scroll compressor consists of a fixed scroll having a base with a generally spiral wrap extending from the base towards an orbiting scroll. The orbiting scroll has a base with a spiral wrap extending towards the fixed scroll. The orbiting scroll orbits relative to the fixed scroll and compression chambers between the intermeshing scroll wraps are compressed.
It is a desire of the scroll compression industry to minimize the size of the scroll compressor. In particular, it is desirable to minimize the axial length of the scroll compressor. Further, it has been a challenge to remove heat from the scroll compression chambers. Typically, in a sealed scroll compressor, the fixed scroll is mounted at some distance away from an outer housing. Thus, the outer housing is exposed to the ambient environment, but the fixed scroll is separated from the ambient environment, and thus has been somewhat difficult to cool.
The prior art has proposed combining the fixed scroll with the outer housing. However, in general, these designs have proposed bolting the combined fixed scroll and outer housing to a second housing along interface planes. With such a combination it would be difficult to achieve proper positioning of the scroll members, as there is no adjustability provided. Moreover, it is not believed these proposals have ever been in production. To the extent they have, they would be very difficult to assemble.
In a disclosed embodiment of this invention, a scroll compressor comprises a fixed scroll formed integrally with an outer housing. The compressor is preferably in a sealed canister with a generally tubular housing welded to the combined outer housing and fixed scroll. Preferably, the outer housing is positioned on a radially outer surface of the tubular housing and welded.
More preferably, a muffler is formed integrally with the combined housing and fixed scroll. The muffler preferably extends to the side of the compressor such that it does not increase the overall axial length. Fins also extend from the combined housing and fixed scroll in a direction away from the fixed scroll wrap. The fins provide cooling to remove heat from the compression chambers. Preferably, the muffler and the fins extend away from the base of the fixed scroll member for an approximately equal distance.
In a most preferred embodiment, the combined housing and fixed scroll includes inner and outer tubular portions with the tubular housing member fitting between the inner and outer portions. The tubular housing member can move into and out of a channel formed between the inner and outer tubular portions to allow relative adjustment of the position of the housings. In this way, the position of the scroll members can be carefully controlled. Other housing would also come within the scope of this invention. As one example, only the inner portion need be utilized, with the outer guide portion being eliminated. The tubular housing would still be guided along the inner guide portion and welded.
In a method of assembling the scroll compressor according to this invention, a pump unit is initially assembled by securing the main crankcase bearing to the combined fixed scroll and outer housing. The orbiting scroll is captured between the crankcase and the fixed scroll. This sub-assembly is then welded to the tubular housing member. Thus, the main crankcase bearing is directly and rigidly secured to the outer housing through this outer weld joint. This provides additional strength to the bearing attachment.
In further embodiments of this invention, the one piece fixed scroll and outer housing may be preferably formed of two parts. A cast iron portion may form the fixed scroll, while a steel portion forms the outer housing. The cast iron portion is preferably pressed into the outer housing, with a generally planar interface between the two ensuring the two will be in tight contact to ensure proper positioning and good heat transfer. This two-piece part will be beneficial in that forming the entire combined member of the cast steel could be costly, and it may be difficult to cast the thin scroll wraps. It potentially also may be complicated to machine steel wraps. Thus, having the two-piece part, provides the outer housing formed of steel, with the scroll wraps formed of a more easily machined material such as cast iron or aluminum.
In a further embodiment of this invention, heat pipes are attached to the outer surface of the one-piece fixed scroll and outer housing. The heat pipes are preferably utilized in combination with fins which attach to the several heat pipes. Further, the condenser fan may be mounted adjacent to the end of the housing such that the fan will draw air over the heat pipes and fins. While heat pipes are shown as the heat exchanger attached to the outer surface of the fixed scroll and outer housing, it should be understood that other separate heat exchangers attached to the housing would come within the scope of this invention.
These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description.